package com.momo.theta.config;

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;

public class SpringContextHolder implements ApplicationContextAware {

  /**
   * 以静态变量保存Spring ApplicationContext, 可在任何代码任何地方任何时候中取出ApplicationContext.
   */
  private static ApplicationContext applicationContext;

  /**
   * 取得存储在静态变量中的ApplicationContext.
   */
  public static ApplicationContext getApplicationContext() {
    return applicationContext;
  }

  /**
   * 实现ApplicationContextAware接口的context注入函数, 将其存入静态变量.
   */
  @Override
  public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
    SpringContextHolder.applicationContext = applicationContext;
  }

  /**
   * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
   */
  @SuppressWarnings("unchecked")
  public static <T> T getBean(String name) {
    checkApplicationContext();
    return (T) applicationContext.getBean(name);
  }

  /**
   * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
   */
  @SuppressWarnings("unchecked")
  public static <T> T getBean(Class<T> clazz) {
    checkApplicationContext();
    return (T) applicationContext.getBeansOfType(clazz);
  }

  /**
   * 指定名称和类型返回指定的对象
   */
  public static <T> T getBean(String name, Class<T> requiredType) {
    return applicationContext.getBean(name, requiredType);
  }

  /**
   * 清除applicationContext静态变量.
   */
  public static void cleanApplicationContext() {
    applicationContext = null;
  }

  /**
   * 检查注册方法
   */
  private static void checkApplicationContext() {
    if (applicationContext == null) {
      throw new IllegalStateException(
          "do not have applicationContext,please inject applicationContext");
    }
  }

}